Vitamin E, lipids, and lipid peroxidation products in tardive dyskinesia

BACKGROUND

Lipid peroxidation has been postulated as a possible mechanism for neuronal damage in tardive dyskinesia, and this is supported by evidence of increased lipid peroxidation products in the cerebrospinal fluid of dyskinetic subjects.

METHODS

In this study plasma levels of vitamin E and vitamin A, measured by high-performance liquid chromatography, and of thiobarbituric acid-reactive substances (TBARS), were determined in 16 schizophrenic patients with tardive dyskinesia, 16 nondyskinetic patients all assessed by Abnormal Involuntary Movement Scale (AIMS), and 10 normal control subjects. Plasma cholesterol and triglyceride were also measured throughout. Vitamin E levels in plasma were corrected for total lipids.

RESULTS

Multivariate analysis of covariance showed significant differences when vitamin E and TBARS were compared in the three groups. Univariate t tests showed a significantly lower lipid-corrected vitamin E (p = .018) between the normal and dyskinetic group but not between the normal and the nondyskinetic schizophrenic patients. There was no difference in vitamin A levels between patients and normal controls. TBAR results showed a significant positive correlation between AIMS score and lipid-corrected TBARS.

CONCLUSIONS

This study confirms an abnormality associating lipid peroxidation and tardive dyskinesia and extends this abnormality to measurements of lipid-corrected vitamin E in plasma.

High-resolution separation and quantification of neutral lipid and phospholipid species in mammalian cells and sera by multi-one-dimensional thin-layer chromatography

An improvement of current methods is needed for simple, rapid, and precise quantification of cellular lipids, including rare species of biologically active cellular lipids, such as phosphatidic acid (PA) and diradylglycerol (DG). In addition, further analysis of hydrolyzed acyl chains from these species by methods such as gas chromatography requires complete separations. Methods have been developed for the quantification of neutral lipids and several phospholipids extracted from mammalian cells and sera. Lipid masses were determined for the major classes of the neutral, nonpolar lipids, and of the phospholipids. The lipid classes were separated by a multistep thin-layer chromatography (TLC) procedure in different solvent systems, a method which we have designated as multi-one-dimensional thin-layer chromatography (MOD-TLC). Resolved lipid bands were visualized by the lipophilic dye primulin (direct yellow 59) and scanned by an automated laser-fluorescence detector. The mass of each band was determined by comparing band intensities of unknown samples to dilution curves of authentic standards. With modifications in solvent mixtures and length of separation times, the majority of biological lipids could be resolved and quantified with MOD-TLC methods. Since the detection method is nondestructive, purified lipids could then be recovered by scraping the visualized bands and extracting the lipids from the silica. The structural identities of the recovered lipids were confirmed by fast-atom bombardment and electrospray mass spectrometry. Extracted lipids were also hydrolyzed to release acyl chains and acyl chain species were determined in comparison to authentic standards by gas chromatography. PA and DG levels in ECV.304 cells were found to be 4. 6 and 3.3%, respectively, of PC levels, with a PA/DG ratio of 1.4, which is in accord with published experience using other methods and different cell types. PA in human serum was detected at 0.6% of PC, indicating the sensitivity of the technique. In contrast to two-dimensional thin-layer chromatography, which allows for good resolution of some lipid species, but cannot be used to analyze more than a single experimental point per plate, MOD-TLC allows for direct comparative analysis of multiple samples on a single TLC plate, while still providing good resolution for the quantification of most major classes of lipid species.

Molecular cloning of two alternatively spliced forms of human phosphatidic acid phosphatase cDNAs that are differentially expressed in normal and tumor cells

Phosphatidic acid (PA) and diacylglycerol (DG) are lipids involved in signal transduction and in structural membrane-lipid biosynthesis in cells. Phosphatidic acid phosphatase (PAP) catalyzes the conversion of PA to DG. This enzyme exists in at least two isoforms, one of which (PAP1) is presumed to be cytosolic and membrane associated and the other (PAP2) to be an integral membrane protein. Homology search of the GenBank database using a murine sequence probe enabled the cloning of several putative human isoenzymes. Two isoforms, presumed to be alternative splice variants from a single gene, designated as PAP2-alpha1 and PAP2-alpha2, have been cloned and expressed. The PAP2-alpha1 and PAP2-alpha2 have a 84% and a 72% overall match, respectively, with the published mouse PAP amino acid sequence. The area of alternative exon usage was confined to the coding region at amino acids 20 to 70. Ectopic expression of PAP2-alpha1 and PAP2-alpha2 cDNAs in ECV304 endothelial cells led to a 6- to 8-fold and a 2-fold increase in PAP activity, respectively, in cell-free extracts using an in vitro assay that measured the conversion of [14C]PA to [14C]DG. The increase in PAP activity in PAP2-alpha-transfected cells correlated with a >50% decrease in the steady-state PA level. Northern analysis showed that PAP2-alpha mRNA expression was suppressed in several tumor tissues, notably those derived from the lower alimentary tract. Subsequent analysis of colon tumor tissue derived from four donors confirmed lower expression of PAP2-alpha than in matching normal colon tissue. Considering these data and previous demonstrations that certain transformed cell lines have lower PAP activity, we suggest that human PAP cDNAs may be candidates for gene therapy for certain tumors.

Quantitative analysis of polychlorinated biphenyls, organochlorine insecticides, polycyclic aromatic hydrocarbons, polychlorinated hydrocarbons and polynitrohydrocarbons in spiked samples of soil, water and plasma by selected-ion monitoring gas chromatography-mass spectrometry

A broad range of pollutants such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated hydrocarbons (PCHs), polynitrohydrocarbons (PNHs), polychlorinated biphenyls (PCBs) and organochlorine (OCs) insecticides were simultaneously analyzed in spiked soil, water or plasma samples by using gas chromatography-mass spectrometry (GC-MS). Water and plasma samples containing the pollutants were extracted by a solid-phase extraction (SPE) method using florisil columns. The soil samples, fortified with the toxicants, were extracted with water, methanol or dichloromethane (DCM). The water extract was processed by the SPE method. The methanol and DCM samples were dried, dissolved in acetonitrile and subjected to the SPE extraction. The extracted samples were analyzed by GC-MS programmed to monitor selected ions. The deuterium labelled compounds were used as the internal standards. The chromatographic profile of total ions indicated complete separation of some compounds such as isophorone, naphthalene, all PCBs, most OC insecticides and PNHs; high Mr PAHs and some PCHs were partially or incompletely separated. The chromatographic profile of individual ion indicated good separation of each ion. The minimum detection limit ranged from 1 to 4 pg injected when 1 or 2 ions were monitored or from 20 to 200 pg injected when 20 ions were monitored. The SPE method that provided 60-105% recovery of pollutants from water samples, provided only 2-60% recovery from plasma samples. This may be due to the binding of pollutants to plasma proteins. Water recovered 1-30%, while methanol or DCM recovered 65-100% of the pollutants added to the soil samples. The use of internal standards corrected for the loss of pollutants from plasma or soil.

Prolonged discordant xenograft survival by inhibition of the intrinsic coagulation pathway in complement C6-deficient recipients

BACKGROUND

Xenotransplantation of vascularized organs between unmodified discordant species results in hyperacute graft rejection within minutes to hours after graft reperfusion. This process is due to the presence of natural xenoreactive antibodies and complement activation, which lead to vessel injury, thrombosis, and hemorrhage. Because multiple components of the coagulation and complement cascades interact with each other, we have investigated the effects of inhibiting these systems together. The recombinant Kunitz type serine protease inhibitor (KPI-BG022) tested in these experiments inhibits factor XIIa, kallikrein, and plasmin.

METHODS

Cardiac xenografts from male Hartley guinea pigs were heterotopically grafted into male PVG rats that were either sufficient (C6[+]) or deficient (C6[-]) for the complement component C6 and thus formation of the membrane attack complex. Experimental animals received KPI 5 mg/kg intravenously before reperfusion, and control animals received saline placebo.

RESULTS

C6(+) recipients rejected their grafts hyperacutely, without a significant difference between KPI-treated (0.12+/-0.05 hours) and placebo-treated (0.13+/-0.06 hours) recipients (n = 10). As expected, C6(-) recipients showed prolonged graft survival (17.65+/-3.45 hours, n = 5). However, a single intravenous bolus of KPI before releasing the clamps further delayed graft rejection in C6(-) recipients (46.2+/-3.3 hours; n = 5). Histologic examination at 2, 6, and 12 hours after transplantation showed platelet aggregation and inflammatory infiltrates were significantly decreased in KPI-treated (C6[-]) recipients. However, intragraft hemorrhage was apparent at 6 and 12 hours.

CONCLUSIONS

We conclude that in vivo inhibition of the intrinsic clotting cascade by functional inactivation of factor XIIa has a synergistic effect with inhibition of membrane attack complex formation in preventing hyperacute discordant xenograft rejection.

First Report of Inonotus tomentosus, the Cause of Tomentosus Root Disease, from the Yukon Territory

During forest pest surveys in the Watson Lake area (60°N 129°W) of the Yukon Territory (YT), sporocarps, tentatively identified as Inonotus tomentosus (Fr.:Fr.) S. Teng, were observed in association with old mortality (25+ years) and root rot of old (200 to 275 years) white spruce (Picea glauca (Moench) Voss) growing in riparian zones. I. tomentosus primarily attacks spruce throughout North America (1). Cultures from collected sporocarps and from a decayed root of a living tree produced chlamydospore-like hyphal swellings typical of I. tomentosus(2). Although three of the collected sporocarps were bracketlike, none bore hooked hymenial setae, typical of I. circinatus (Fr.) R. L. Gilbertson. All sporocarps collected possessed straight setal hyphae and were confirmed as I. tomentosus (1). These specimens are filed at the Pacific Forestry Centre herbarium as DAVFP 25375 and DAVFP 25376. This is the first western Canadian report of this major conifer root disease north of about 55°N latitude. Sporocarps have been collected at about the same latitude as Watson Lake, but from 21° farther west, near Fairbanks and Anchorage, AK (L. Trummer, USDA For. Serv. Anchorage, AK, personal communication). For several years, other stump and root decay samples have been collected in the YT as far west as Haines Junction (about halfway between Anchorage and Watson Lake), but the pathogen has never been successfully cultured nor sporocarps collected. Because the decay pattern can be confused with that caused by Phellinus pini (Thore:Fr.) A. Ames, and other diagnostic features were lacking, there has been a reluctance to accept that I. tomentosus is present in the YT. However, it seems likely that I. tomentosus is much more widespread north of 55°N in western Canada than has previously been recognized. References: (1) R. L. Gilbertson and L. Ryvarden. North Am. Polypores. Fungiflora 1:403, 1986. (2) R. S. Hunt. Can. J. Plant Pathol. 19:307, 1997.

Physicochemical, molecular-orbital and electronic properties of acephate and methamidophos

Methamidophos (Me) and its N-acetylated derivative, acephate (Ac), are water soluble insecticides that have similar insecticidal potency, but different mammalian toxicity. Me is a potent inhibitor, while Ac is a poor inhibitor of mammalian AChE (mAChE). At physiological pH, both insecticides exhibit similar accumulation in RBC, while Ac exhibits greater binding to plasma proteins than Me. These differential effects of Ac and Me are attributed to the differences in their physicochemical, molecular-orbital and electronic properties. Ac and Me are freely soluble in aqueous solution, moderately soluble in ethyl-acetate (EtAct) and insoluble in n-hexane. The solubility of these insecticides in aqueous solution and the partitioning of these insecticides from aqueous solution into EtAct are independent of the pH of the aqueous solution. At pH 8, Me did not react with o-phthalaldehyde (a NH2 selective dye), but gamma-amino-butyric acid (pKa 10) did. Thus, despite the presence of an amino group, Ac and Me do not exhibit pH dependent solubility in aqueous and in organic solvents. Ac has two O atoms with non-bonding electrons (P = O delta- and C = O delta-) where P = O and C = O point in opposite directions. Me has only one O atom with non-bonding electrons (P = O delta-). However, because of charge translocation, the C = O group of Ac exists as C = O- and the P-NH3+ group of Me exists as P = NH2+ at a pH lower than their pKa. The P-N bond of Me, but not of Ac, is hydrolyzed at pH 2. Thus, the presence of an electron rich domain stabilizes Ac's P-N bond. The CH3S-P bond of both insecticides is similarly hydrolyzed at pH 11. This indicates that the two compounds are considerably similar except that Ac has an additional electron rich domain. At physiological pH, therefore, the functional differences between these insecticides may be due to the differences in their electronic structure. We propose that, similar to a previous model for cationic inhibitors of AChE (13), the P = O delta- group of Me forms hydrogen bonds within the oxyanion-hole causing the leaving group (-SCH3) to orient towards the "gorge" opening. This orientation allows the P atom of Me to interact with Ser200, resulting in the phosphorylation of the enzyme. For acephate, either P = O or C = O, but not both, interact within the oxyanion-hole. This destabilizes the binding of Ac to the active center, resulting in reduced AChE phosphorylation.

Comparison of teaching the basic electrocardiographic concept of frontal plane QRS axis using the classical versus the orderly electrocardiogram limb lead displays

This study compares the effectiveness of teaching the calculation of frontal plane QRS axis with the use of the classical versus the orderly electrocardiographic limb lead display. Eighty-three students from two environments were randomized into two groups and were taught to determine frontal plane axis with one of the methods. The accuracy and time to determine the axis were tested on 10 electrocardiograms. In the United States the group using the classical display achieved 4.2 (+/-2.7) correct answers, whereas those using the orderly method achieved 6.8 (+/-3.0) (p = 0.0006). The classical group used 9.2 (+/-2.8) minutes to complete the test, whereas the orderly group needed 7.2 (+/-2.0) minutes (p = 0.015). The results achieved in Sweden were similar. The use of the orderly electrocardiographic limb lead display results in greater diagnostic accuracy in less time than the classical display when determining the frontal plane QRS axis.

List-mode likelihood

As photon-counting imaging systems become more complex, there is a trend toward measuring more attributes of each individual event. In various imaging systems the attributes can include several position variables, time variables, and energies. If more than about four attributes are measured for each event, it is not practical to record the data in an image matrix. Instead it is more efficient to use a simple list where every attribute is stored for every event. It is the purpose of this paper to discuss the concept of likelihood for such list-mode data. We present expressions for list-mode likelihood with an arbitrary number of attributes per photon and for both preset counts and preset time. Maximization of this likelihood can lead to a practical reconstruction algorithm with list-mode data, but that aspect is covered in a separate paper [IEEE Trans. Med. Imaging (to be published)]. An expression for lesion detectability for list-mode data is also derived and compared with the corresponding expression for conventional binned data.

Validation of nonradioactive chemiluminescent immunoassay methods for the analysis of thyroxine and cortisol in blood samples obtained from dogs, cats, and horses

The performances of a radioimmunoassay method, a chemiluminescent immunoassay method, and a chemiluminescent-enzyme immunoassay method were evaluated for the analysis of cortisol and total thyroxine in blood samples obtained from dogs, cats, horses, and humans (reference samples). The analysis of cortisol in human and animal samples exhibited good precision, linearity, and recovery. The 3 methods gave comparable values for the ACTH-induced increase and the dexamethasone-induced decrease in cortisol concentrations in animal samples. The recoveries of total thyroxine from human samples, analyzed by the 3 methods, were comparable. However, the basal total thyroxine concentrations determined by the chemiluminescent immunoassay method were 30-40% lower than those determined by the radioimmunoassay and the chemiluminescent-enzyme immunoassay methods in animal samples. In both human and animal samples, the plot of thyroxine values obtained by the radioimmunoassay method against those obtained by the chemiluminescent immunoassay method or the chemiluminescent-enzyme immunoassay method was linear. However, although the slope of the radioimmunoassay versus chemiluminescent-enzyme immunoassay curve was close to unity, the slope of the radioimmunoassay versus chemiluminescent immunoassay curve was 0.6. This result suggests that, compared with the radioimmunoassay method, the chemiluminescent immunoassay method underestimated thyroxine values in animal samples but not in human samples. Although all 3 methods yielded comparable changes in thyroxine concentrations in response to thyroid stimulating hormone, they did not yield comparable thyroxine concentrations in response to T3 suppression in dogs and cats.

Cloning and expression of two human lysophosphatidic acid acyltransferase cDNAs that enhance cytokine-induced signaling responses in cells

Lysophosphatidic acid (LPA) and phosphatidic acid (PA) are two phospholipids involved in signal transduction and in lipid biosynthesis in cells. LPA acyltransferase (LPAAT), also known as 1-acyl sn-glycerol-3-phosphate acetyltransferase (EC 2.3.1.51), catalyzes the conversion of LPA to PA. In this study, we describe the isolation and characterization of two human cDNAs that encode proteins possessing LPAAT activities. These two proteins, designated here as LPAAT-alpha and LPAAT-beta, contain extensive sequence sequence similarities to microbial or plant LPAAT sequences. LPAAT-alpha mRNA was detected in all tissues with highest expression in skeletal muscle whereas LPAAT-beta was expressed predominantly in heart and liver tissues. Expression of these two cDNAs in an Escherichia coli strain with a mutated LPAAT gene (plsC) complements its growth defect and shifts the equilibrium of cellular lipid content from LPA to PA and other lipids. Overexpression of these two cDNAs in mammalian cells leads to increased LPAAT activity in cell-free extracts using an in vitro assay that measures the conversion of fluorescently labeled LPA to PA. This increase in LPAAT activity correlates with enhancement of transcription and synthesis of tumor necrosis factor-alpha and interleukin-6 from cells upon stimulation with interleukin-1beta, suggesting LPAAT overexpression may amplify cellular signaling responses from cytokines.

Calreticulin-integrin bidirectional signaling complex

Calreticulin has multiple functions, diverse cellular locations, and putative isoforms. It likely maintains integrin avidity by binding alpha integrin cytoplasmic tails and is a surface lectin which triggers cell spreading. In the present study, we have immunocaptured a cell surface complex from B16 mouse melanoma cells which contains alpha 6 beta 1 integrin, two molecular forms of calreticulin, and KDEL docking protein (KDEL-R). One of the calreticulins, "endocalreticulin", a 52 kDa protein, does not become surface biotinylated, and is probably bound to alpha integrin cytoplasmic tails; it disappears when B16 cells adhere to laminin, and two ubiquitinated calreticulins appear. One ubiquitinated species, a 125 kDa protein, is restricted to focal contacts whereas a second species, a 75 kDa protein, is in focal contacts and surrounding plasma membrane; it also arises when cells bind non-specific surfaces. The other calreticulin, "ectocalreticulin", a 62 kDa protein, becomes surface biotinylated, is probably anchored to surface KDEL-R, and cooperates with alpha 6 beta 1 integrin, triggering cell spreading. The present results suggest a model in which calreticulin-integrin surface complex functions as a symbiotic unit, transmitting information in both directions across the plasma membrane.

Analysis of selenium in bovine liver by gas chromatography with mass-selective, electron-capture and nitrogen-phosphorus detection

The concentration of selenium (Se) in liver was determined by gas chromatography (GC) with mass-selective (GC-MS), electron capture (GC-ECD) and nitrogen-phosphorus (GC-NPD) detection. Liver samples were digested in a mixture containing HNO3 and Mg(NO3). SeVI was converted to SeIV. SeIV was derivatized with 4-nitrophenylenediamine and then extracted in toluene. A 1-microliter volume of the toluene extract was analyzed by the GC-MS, GC-ECD or GC-NPD methods. The detection limits of the GC-ECD, the GC-NPD and the GC-MS methods were 25, 50 and 800 pg, respectively. The GC-NPD method was more selective for the derivatized Se than the GC-ECD method. The GC-MS method had the advantage of using the 76Se isotope as the internal standard. Se concentrations in liver samples determined by the three methods were comparable.

A new procedure for establishing functional monoclonal antibodies capable of inhibiting E- or P-selectin-dependent cell adhesion

Employing a new procedure, we established many monoclonal antibodies (mAbs) which inhibit E- or P-selectin-dependent cell adhesion. One of these mAbs is capable of staining selectin in paraffin-embedded histological sections. The procedure is based on immunization of BALB/c mice with irradiated mouse myeloma NS-1 cells (syngeneic HAT-sensitive fusion partner cells) transfected with cDNA encoding human E- or P-selectin. Resulting NS-1 transfectant cells permanently express human E- or P-selectin as immunogen. The mAbs are useful for detecting selectins by flow cytometric and immunohistological methods, and for inhibiting selectin-dependent adhesion in experimental models. In contrast, the majority of anti-selectin mAbs previously established do not have these capabilities.

Crossing boundaries: communication between professional groups

The NHS reforms increased emphasis on a managerial culture. In primary care this raised questions about responsibility and philosophical approaches. Greater integration between agencies brings benefits, but creates tensions. Failure to bridge the gap may result in dysfunctional teams and compromised quality of patient care. The different orientations may manifest themselves in several ways but lead to frictions that can breed hostility and prevent effective teamwork. Explores issues involving social service and community nurse teams in Dorset to identify a new framework for working, by recognizing and respecting differences and by creating a climate of dialogue. The process involves three stages. First, mutual awareness by use of meta planning which revealed several important themes, different priorities, political dynamics and organizational constraints. Second, behavioural contracting facilitated by role reversal and third, the development of consensus working protocols as a bridge for professional gaps.

Medicine and management: a conflict facing general practice?

Partners and practice managers are beginning to understand implications of management issues raised by recent reforms. Practices involved in this study agree the need for improvement, but partners and managers were often unable to define improvements needed. Demonstrates that effective management structure is vital to future success for general practice. To achieve this involves understanding new managerial challenges practices must meet and different organizational competences required. To change requires a radical restructure of many practice roles and several options are considered. Regardless of the chosen option the question of training remains. There is a need to involve consultants, managers, and doctors already advancing the boundaries of practice development, in a dialogue with institutions providing management training, to design suitable programmes. Academic institutions too often produce management programmes geared towards the old environment, whereas managerial skills which changes in the NHS demand from future practice managers are now required.

Caudate nucleus area in drug-induced parkinsonism

This study examined caudate nuclei areas in 10 schizophrenic subjects with and 25 schizophrenic subjects without parkinsonian symptoms. The subjects with parkinsonian symptoms were found to have statistically significantly smaller right caudate nuclei and a trend towards smaller left caudates. Cortical measurements did not differ between the groups. These results are consistent with the suggestion that antipsychotic drugs exert some neurotoxic effects, but should be viewed as preliminary and require replication.

Caudate nucleus morphology in tardive dyskinesia

OBJECTIVE

The objective of this project was to test whether there are differences in the size of the caudate nucleus in schizophrenic in-patients with and without tardive dyskinesia.

METHOD

The study was cross-sectional in design, examining group differences between institutionalised schizophrenic patients with and without tardive dyskinesia, using non-enhanced computerised tomography scans of the brain. The group comprised 15 schizophrenic patients with persistent tardive dyskinesia and 21 in-patient schizophrenic controls who were group-matched for demographic variables.

RESULTS

The dyskinetic subjects had a significantly larger left caudate nucleus and tended to have a larger right caudate nucleus than the controls. There were no differences between the groups on any of the measures of cerebral atrophy.

CONCLUSIONS

The findings can be understood within the context of models of neostriatal function. It is possible that a larger caudate nucleus could be used to identify patients at risk of developing tardive dyskinesia.

Detection of Trypanosoma brucei spp. in human blood by a nonradioactive branched DNA-based technique

We have developed a nonradioactive branched DNA (bDNA)-based assay for the diagnosis of the African trypanosomiases in simple buffy coat preparations of human blood. Two repetitive DNA sequences specific to the Trypanosoma brucei complex were chosen as targets of the bDNA assay, a technique which amplifies the signal from a target molecule rather than the target itself. Comparable sensitivities were observed with cloned target sequences, purified T. brucei DNA, procyclic trypanosomes, and bloodstream trypomastigotes. The results of bDNA analysis of human blood samples from Côte d'Ivoire (n = 50) showed excellent agreement with those of buffy coat microscopy. The bDNA technology offers certain advantages over alternative molecular biological techniques, including the simplicity of sample preparation and of the procedure itself, the stability of the reagents, the ability to process large numbers of samples simultaneously, and freedom from crosscontamination artifacts. We have successfully applied the bDNA technique to the detection of T. brucei in clinical samples from regions where T. brucei infection is endemic; to our knowledge, this is the first report of the molecular detection of T. brucei in human blood.

Lung function in premature rabbits treated with recombinant human surfactant protein-C

We report the activity of recombinant human surfactant apoprotein-C (rSP-C[Cys]2) and various phospholipids in a preterm rabbit model of respiratory distress syndrome (RDS). Mixtures of rSP-C(Cys)2 and certain phospholipids had similar activity (lung compliance and lung pressure-volume behavior) to rabbit surfactant in this model. The activity of rSP-C(Cys)2 was maximal at 1 mol% protein and varied significantly with the phospholipid composition. Chemically synthesized SP-C had similar activity to rSP-C(Cys)2. Deletion of six amino-terminal residues did not affect function. Substitution of cysteines and cysteine6 with adjacent serines (rSP-C[Ser]2) by site-specific mutagenesis minimized aggregation of rSP-C but did not affect activity. Palmitoylation of cysteine5 and cysteine6 in rSP-C (rSP-C[C16]2) did not enhance the activity of rSP-C(Cys)2. We conclude that bacterial expression is a practical source of functional SP-C, and that nonacylated forms of SP-C may be useful adjuvants to phospholipids in the treatment of RDS and possibly other forms of acute lung injury.

Mucosal permeability of ileal and colonic reservoirs for urine

OBJECTIVES

To evaluate the intestinal mucosal permeability in continent reservoirs for urine.

PATIENTS AND METHODS

The mucosal permeability in continent urinary reservoirs, constructed either from an ileal or a colonic segment (six patients each), was assessed by analysing serial samples of plasma, after instilling the reservoir with 51Cr-ethylene diaminetetra-acetic acid (51Cr-EDTA), and serum, after instillation with polyethylene glycol (PEG 400).

RESULTS

There was no or negligible permeation of 51Cr-EDTA and PEG 400 in either type of reservoir, as there was no significant increase of the markers in plasma and serum, respectively.

CONCLUSION

The intestinal barrier to medium-sized hydrophilic molecules seems intact in continent urinary reservoirs. The lack of significant permeation of 51Cr-EDTA confirms the usefulness of a single injection of 51Cr-EDTA for the determination of glomerular filtration rate in patients with intestinal urinary diversion.